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CMake Maintainer Guide
**********************
The following is a guide to CMake maintenance processes.
See documentation on `CMake Development`_ for more information.
.. _`CMake Development`: README.rst
.. contents:: Maintainer Processes:
Governance
==========
CMake has no formal governance body. Maintainers expect one another to
cooperate constructively and make decisions in good faith. In cases of
disagreement, the chief maintainer retains final authority.
Review a Merge Request
======================
The `CMake Review Process`_ requires a maintainer to issue the ``Do: merge``
command to integrate a merge request. Please check at least the following:
* If the MR source branch (or part of it) should be backported
to the ``release`` branch (and is already based on a commit
contained in the ``release`` branch), add a ``Backport: release`` or
``Backport: release:<commit-ish>`` trailing line to the MR description.
* If the MR source branch is not named well for the change it makes
(e.g. it is just ``master`` or the patch changed during review),
add a ``Topic-rename: <topic>`` trailing line to the MR description
to provide a better topic name.
* If the MR introduces a new feature or a user-facing behavior change,
such as a policy, ensure that a ``Help/release/dev/$topic.rst`` file
is added with a release note.
* If a commit changes a specific area, such as a module, its commit
message should have an ``area:`` prefix on its first line.
* If a commit fixes a tracked issue, its commit message should have
a trailing line such as ``Fixes: #00000``.
* Ensure that the MR adds sufficient documentation and test cases.
* Ensure that the MR has been tested sufficiently. Typically it should
be staged for nightly testing with ``Do: stage``. Then manually
review the `CMake CDash Page`_ to verify that no regressions were
introduced. (Learn to tolerate spurious failures due to idiosyncrasies
of various nightly builders.)
* Ensure that the MR targets the ``master`` branch. A MR intended for
the ``release`` branch should be based on ``release`` but still target
``master``. Use the above-mentioned ``Backport: release`` line to tell
``Do: merge`` to merge to both. If a MR is merged without the backport
line, a maintainer may still merge the MR topic to ``release`` manually.
Maintain Current Release
========================
The ``release`` branch is used to maintain the current release or release
candidate. The branch is published with no version number but maintained
using a local branch named ``release-$ver``, where ``$ver`` is the version
number of the current release in the form ``$major.$minor``. It is always
merged into ``master`` before publishing.
To merge an open MR to the ``release`` branch, edit its description to
use the ``Backport: release`` line mentioned above and then ``Do: merge``
normally. To update the ``release`` branch manually (e.g. to merge a
``$topic`` branch that was merged without the backport line), use the
following procedure.
Before merging a ``$topic`` branch into ``release``, verify that the
``$topic`` branch has already been merged to ``master`` via the usual
``Do: merge`` process. Then, to merge the ``$topic`` branch into
``release``, start by creating the local branch:
.. code-block:: shell
git fetch origin
git checkout -b release-$ver origin/release
Merge the ``$topic`` branch into the local ``release-$ver`` branch, making
sure to include a ``Merge-request: !xxxx`` footer in the commit message:
.. code-block:: shell
git merge --no-ff $topic
Merge the ``release-$ver`` branch to ``master``:
.. code-block:: shell
git checkout master
git pull
git merge --no-ff release-$ver
Review new ancestry to ensure nothing unexpected was merged to either branch:
.. code-block:: shell
git log --graph --boundary origin/master..master
git log --graph --boundary origin/release..release-$ver
Publish both ``master`` and ``release`` simultaneously:
.. code-block:: shell
git push --atomic origin master release-$ver:release
.. _`CMake Review Process`: review.rst
.. _`CMake CDash Page`: https://open.cdash.org/index.php?project=CMake
Create Release Version
======================
When the ``release`` branch is ready to create a new release, follow the
steps in the above `Maintain Current Release`_ section to checkout a local
``release-$ver`` branch, where ``$ver`` is the version number of the
current release in the form ``$major.$minor``.
Edit ``Source/CMakeVersion.cmake`` to set the full version:
.. code-block:: cmake
# CMake version number components.
set(CMake_VERSION_MAJOR $major)
set(CMake_VERSION_MINOR $minor)
set(CMake_VERSION_PATCH $patch)
#set(CMake_VERSION_RC $rc) # uncomment for release candidates
In the following we use the placeholder ``$fullver`` for the full version
number of the new release with the form ``$major.$minor.$patch[-rc$rc]``.
If the version is not a release candidate, comment out the RC version
component above and leave off the ``-rc$rc`` suffix from ``$fullver``.
Commit the release version with the **exact** message ``CMake $fullver``:
.. code-block:: shell
git commit -m "CMake $fullver"
Tag the release using an annotated tag with the same message as the
commit and named with the **exact** form ``v$fullver``:
.. code-block:: shell
git tag -s -m "CMake $fullver" "v$fullver"
Follow the steps in the above `Maintain Current Release`_ section to
merge the ``release-$ver`` branch into ``master`` and publish both.
Branch a New Release
====================
This section covers how to start a new ``release`` branch for a major or
minor version bump (patch releases remain on their existing branch).
In the following we use the placeholder ``$ver`` to represent the
version number of the new release with the form ``$major.$minor``,
and ``$prev`` to represent the version number of the prior release.
Review Prior Release
--------------------
Review the history around the prior release branch:
.. code-block:: shell
git log --graph --boundary \
^$(git rev-list --grep="Merge topic 'doc-.*-relnotes'" -n 1 master)~1 \
$(git rev-list --grep="Begin post-.* development" -n 1 master) \
$(git tag --list *-rc1| tail -1)
Consolidate Release Notes
-------------------------
Starting from a clean work tree on ``master``, create a topic branch to
use for consolidating the release notes:
.. code-block:: shell
git checkout -b doc-$ver-relnotes
Run the `consolidate-relnotes.bash`_ script:
.. code-block:: shell
Utilities/Release/consolidate-relnotes.bash $ver $prev
.. _`consolidate-relnotes.bash`: ../../Utilities/Release/consolidate-relnotes.bash
This moves notes from the ``Help/release/dev/*.rst`` files into a versioned
``Help/release/$ver.rst`` file and updates ``Help/release/index.rst`` to
link to the new document. Commit the changes with a message such as::
Help: Consolidate $ver release notes
Run the `Utilities/Release/consolidate-relnotes.bash` script to move
notes from `Help/release/dev/*` into `Help/release/$ver.rst`.
Manually edit ``Help/release/$ver.rst`` to add section headers, organize
the notes, and revise wording. Then commit with a message such as::
Help: Organize and revise $ver release notes
Add section headers similar to the $prev release notes and move each
individual bullet into an appropriate section. Revise a few bullets.
Update Sphinx ``versionadded`` directives in documents added since
the previous release by running the `update_versions.py`_ script:
.. code-block:: shell
Utilities/Sphinx/update_versions.py --since v$prev.0 --overwrite
.. _`update_versions.py`: ../../Utilities/Sphinx/update_versions.py
Commit the changes with a message such as::
Help: Update Sphinx versionadded directives for $ver release
Run the script:
Utilities/Sphinx/update_versions.py --since v$prev.0 --overwrite
Open a merge request with the ``doc-$ver-relnotes`` branch for review
and integration. Further steps may proceed after this has been merged
to ``master``.
Update 'release' Branch
-----------------------
Starting from a clean work tree on ``master``, create a new ``release-$ver``
branch locally:
.. code-block:: shell
git checkout -b release-$ver origin/master
Remove the development branch release note infrastructure:
.. code-block:: shell
git rm Help/release/dev/0-sample-topic.rst
sed -i '/^\.\. include:: dev.txt/ {N;d}' Help/release/index.rst
Commit with a message such as::
Help: Drop development topic notes to prepare release
Release versions do not have the development topic section of
the CMake Release Notes index page.
Update ``Source/CMakeVersion.cmake`` to set the version to
``$major.$minor.0-rc0``:
.. code-block:: cmake
# CMake version number components.
set(CMake_VERSION_MAJOR $major)
set(CMake_VERSION_MINOR $minor)
set(CMake_VERSION_PATCH 0)
set(CMake_VERSION_RC 0)
Replace uses of ``DEVEL_CMAKE_VERSION`` in the source tree with
the literal release version number string ``"$major.$minor.0"``:
.. code-block:: shell
$EDITOR $(git grep -l DEVEL_CMAKE_VERSION)
Commit with a message such as::
Begin $ver release versioning
Merge the ``release-$ver`` branch to ``master``:
.. code-block:: shell
git checkout master
git pull
git merge --no-ff release-$ver
Begin post-release development by restoring the development branch release
note infrastructure, and the version date from ``origin/master``:
.. code-block:: shell
git checkout origin/master -- \
Source/CMakeVersion.cmake Help/release/dev/0-sample-topic.rst
sed -i $'/^Releases/ i\\\n.. include:: dev.txt\\\n' Help/release/index.rst
Update ``Source/CMakeVersion.cmake`` to set the version to
``$major.$minor.$date``:
.. code-block:: cmake
# CMake version number components.
set(CMake_VERSION_MAJOR $major)
set(CMake_VERSION_MINOR $minor)
set(CMake_VERSION_PATCH $date)
#set(CMake_VERSION_RC 0)
Commit with a message such as::
Begin post-$ver development
Create a topic branch for the update to ``master``:
.. code-block:: shell
git branch branch-$ver master
Open a merge request with the ``branch-$ver`` branch for review and CI.
Add the following trailing lines in the merge request description::
Fast-forward: true
Backport-ff: release:HEAD~1^2
This configures the ``Do: merge`` action to fast-foward the ``master``
and ``release`` branches to the respective commits created above.
Further steps may proceed after this has been merged.
Announce 'release' Branch
-------------------------
Post a topic to the `CMake Discourse Forum Development Category`_
announcing that post-release development is open::
I've branched `release` for $ver. The repository is now open for
post-$ver development. Please rebase open merge requests on `master`
before staging or merging.
.. _`CMake Discourse Forum Development Category`: https://discourse.cmake.org/c/development
Initial Post-Release Development
--------------------------------
Deprecate policies more than 8 release series old by updating the
policy range check in ``cmMakefile::SetPolicy``.
Commit with a message such as::
Add deprecation warnings for policies CMP#### and below
The OLD behaviors of all policies are deprecated, but only by
documentation. Add an explicit deprecation diagnostic for policies
introduced in CMake $OLDVER and below to encourage projects to port
away from setting policies to OLD.
Update the ``cmake_policy`` version range generated by ``install(EXPORT)``
in ``cmExportFileGenerator::GeneratePolicyHeaderCode`` and
``install_jar_exports`` in ``javaTargets.cmake.in`` to end at the
previous release. We use one release back since we now know all the
policies added for that version. Commit with a message such as::
export: Increase maximum policy version in exported files to $prev
The files generated by `install(EXPORT)`, `export()`, and
`install_jar_exports()` commands are known to work with policies
as of CMake $prev, so enable them in sufficiently new CMake versions.
Update the ``cmake_minimum_required`` version range in CMake itself:
* ``CMakeLists.txt``
* ``Source/Checks/Curses/CMakeLists.txt``
* ``Utilities/Doxygen/CMakeLists.txt``
* ``Utilities/Sphinx/CMakeLists.txt``
to end in the previous release. Commit with a message such as::
Configure CMake itself with policies through CMake $prev